So I want to get something new for my camera and I see that getting a new 70-200 is going to require some more serious saving.

I teach photography to my kids at school using P&S cameras and teaching basic composition and photoshop, (and use my film kit to teach the other kids how to shoot manuall)

But the 70-200mm is a lens I Want for me only, just to shoot sports days for the school since they are happy to pay for my services.

The thing Im wondering, I have now $500 australian bucks and thats enough for a 580ex II and I was thinking, should I skip the flash gun and go for a 70-200 (I moslty shoot special assembly ceremonies and sports) or get the flash to make indoor shots that much more bearable?

What I did with my Oly was use my flash on a tripod, put it at the front of the stage pointing towards the person shaking hands as kids got their awards, they face me and bang, photo wiht a flash.

Or do you think I can get away with using a 70-200 2.8 indoors?

Which do you think is more usefull or which one would you get first? A new tele lens or a new flash gun?

Well, I have a 7D so I dont need wireless anything, but the 580ex II seems like a good idea because I shoot lots of indoor basket ball and also the bounce card is there and I dont have to worry about range once I get it.

Unless someone has a reason not to get the 580 and just get a 430 and maybe a remote switch then I'll go for it - but Im dabbling in stuff I dont normally know much about.

Well, I have the 580EX II and actually it helps a lot - the results are great. I was impressed how much a flash gun can improve the images!

I just wanted the best I could get in order not to have any thoughts like "Well, but there is this stronger flashgun...", "This one is good, but what could I get with the more expensive one...?"
And personally I'm really happy with my choice.

Main reasons for the 580 instead of the 430:
- More strength if needed.
- Weather sealing (yeah! )
- More features.
- Short: The best you can get at the moment.

Canon 580EXII is good for long range. I strongly suspect that at 2.8 it will be hard to stop motion inan indoor sports event with low ISO. Flash will give you the light needed to stop motion and a guide number of 58 is nice for a sports hall.

To borrow (paraphrased) from Joe McNally, I believe in available-light photography, so I make sure I have light available; my 580EX!

Of course, Joe McNally uses Nikon flashguns, not Canon EX. The Canonista counterpart to Joe McNally is Syl Arena, whose new book, already mentioned by ianganderton, is MUCH recommended. It is available from Amazon, so following the link can benefit Cameralabs! This is the book with the smashing pumpkin image on the cover. Syl Arena has a blog, too.

I was lucky; when I started serious photography in 2010, it was with a set-up that my wife had bought from a co-worker. The camera was an XTi, known outside the USA as the 400D. The flashgun was a 580EX! The original owner must have appreciated good flashguns! I later added a Nissin 866 Pro, with comparable power. A 580EX II is on my mental short list, largely for the weather-sealing.

I have also used 220EX and 320EX flashguns, but have not used a 430EX, so I cannot comment on its capabilities.

A 2.8 lens may or may not be enough for indoor shots without flash, but a 580EX is surely an asset indoors and in any low-light scenario. I often shoot indoors at 5.6, 400 ISO, with the flashgun's head tilted forward at about 45 degrees, with the bounce card extended, in E-TTL mode. This works quite well under a wide range of conditions.

I stand by my point. Having the 430ex ii on the 500D without a grip makes it top heavy, and causes 'pull' to the top side. I think I have dropped the camera before because of the weight. Another photographer agrees that the 7D helps to balance out the flash.

As Leo has a 7D, perhaps I should add that the 580EX feels well-balanced on top of my 7D, with no battery grip. Te same is true with my 40D and 5D. On our XTi/400D, a 580EX does make the ensemble top-heavy, which is why I favored a 220EX when I was regularly using the XTi/400D.

I would advise any rebel users to get the 430ex ii over the 580ex ii. You ideally want a 'proper' flash with full manual controls, something which the 220 doesn't have. The closest you will get is the flash exposure compensation.

I have been waiting to get a grip, but want the price to be right. As the 500D is a discontinued product, the prices should fall.